The present invention relates to antibacterial gutta percha for obturation of root canals and, more particularly, to an improved gutta percha point comprising tetracycline and/or iodoform and method for application of the same that yields a broader spectrum of effectiveness based upon the clinical symptomatology in combating the bacterial contamination of leakage and reinfection. The method for application allows the dentist to chose the properly medicated gutta percha point for the individual case.
The aim of endodontic treatment is the elimination of infection from the root canal and the prevention of reinfection within the root canal. Bacteria have long been recognized as the primary etiologic agent of reinfection within the root canal. Proper obturation of the root canal space is a key to this success.
According to the Washington University study nearly 60% of the failures studied occurred because of canal leakage. Salivary fluid, apical fluids, and leakage infiltration due to open lateral canals because of periodontal disease, all contribute to leakage failure and subsequent reinfection of the root canal.
Complete obturation of the root canal is impossible via the universally accepted solid core filling material gutta percha. The usual method of obturation with gutta percha is the lateral condensation technique. This is a compression of the solid gutta percha cones together and adaptation to the canal walls. Numerous studies show leakage alongside the gutta percha cones due to the mere lamination of the gutta percha cones rather than developing a homogenous mass. Even the warm vertical/lateral condensation technique will not give a complete adaptation to the canal walls as shown by several leakage studies, all of which require root canal sealer to attempt to fill in the remaining voids.
Loma Linda University (Torabinejad et al., J. Endo 1990,16:12,566) has also shown that a significant problem in leakage has been through the coronal aspect of the root canal due to delay in placing a permanent restoration, breaking down of the temporary seal, partial fractures or a poorly placed permanent restoration. Over 50% of the root canals were contaminated within 19 days with Streptococcus epidermidis and Proteus vulgaris. 
University of Iowa""s Swanson and Madison (J. Endo, 1987 13:56) found, in their studies that in 82% of the cases, the entire root length was penetrated by bacteria, showing that traditional gutta percha was an inadequate seal.
An attendant problem within the root canal, is the polymicrobial aspect of the contamination. In a combined study, the University of Zurich and University of Umea, Sweden (Nair et al, J. Endo, 1990,16:580), showed that multiple bacterial species and two types of yeasts were found within the canals.
Fabricius"" group extensive studies (Scand. J. Dent Res, 90:134,1982, Scand J. Dent Res, 1982,90: preprint, Scand J. Dent Res, 1982,90: preprint, Scand J Dent Res, 1981, B9:475) at University of Gothenburg, Sweden demonstrated that mixed infections of various bacterial strains were commonplace. His group found that anaerobic strains, especially Bacteroides species were present in longer standing infections and that aerobic or facultative anaerobic bacteria were more common in incipient or shorter to mid term infections.
In the apical region of the root canal, Fabricius found that the fastidious slow growing obligate anaerobic bacterial strains outnumbered the facultative strains. Therefore, bacteria after closure, activated due to leakage by the inadequate seal of gutta percha, will after a time period multiply and reinfect the root canal as they require little or no oxygen to survive and replicate.
Bacteria are also found to have penetrated the dentinal tubules during original infections and cannot be totally eliminated via biomechanical treatment procedures. These lyophilized bacteria will also become active during the leakage phase contributing to reinfection. The bacteria are of both types of Gram strain being positive and negative. However, Gram negative predominates within the canal and both cocci and rods of each type are found. The longer-standing the infection, the more Gram negative rods are found.
The obligate anaerobic portion of root canal infection has been linked to the acute exacerbation or flare up. This is characterized by swelling, pus, pain and bone destruction. This has been corroborated by the benchmark bacteroidies study (J. Endo 15:13,1989) done by Sunqvist at the University of Umea, Sweden. This knowledge has been developed with the advent of the ability now to culture obligate anaerobic Gram negative organisms, These were previously undetected due to lack of this capability in prior bacteriologic studies.
The dentist can now determine, based upon symptomology, bacteriologic studies statistics, and etiology, the most likely type of bacteria present. The dentist then can utilize the correct pharmacologic obturation materials for treatment and preservation of the root canal integrity.
Eguchi et al at the endodontic research clinic, US Army, Ft. Campbell, Ky. (J. Endo, 11:166, 1985) showed that no matter what technique was used with gutta percha for obturation, lateral, vertical heat, mechanical or chemical dip, the range of obturation sealing was 77-95%. This allows sufficient space for the breakdown and reinfection due to leakage contamination to occur, as well as failure due to poor fills, and failure due to inadequate cleaning and disinfection.
Gutta percha is the obturation material of choice. Its antibacterial properties are not significant in its traditional form. The present inventor has previously disclosed in U.S. Pat. No. 5,648,403, issued Jul. 15, 1997, that iodoform 10% in gutta percha has antibacterial properties superior to traditional gutta percha.
However, upon further testing, Iodoform has been shown to be ineffective against tested aerobes such as Streptococcus mutans, Streptococcus sanguis, Escherchi coli, Staphylococcus aureus, and the facultative anaerobe, Enterococci faecium, Actinomyces, Lactobacillus, Prevotella intermedius. This study was accomplished at the Naval Dental School, Bethesda, Md. and the results are as shown in FIG. 1. FIG. 1 indicates that the iodoform/gutta percha of Martin""s previous formulation will not always be effective against all types of organisms but is effective against facultative gram xe2x88x92 and gram + rods and cocci as well as obligate anaerobes. This shows that iodoform gutta percha is more effective against a longstanding infection of the root canal and against organisms present within the oral microbiota that have reduced oxygen potential. However, it is not as effective against an oral salivary leakage contamination as determined by the previous leakage and bacterial investigations.
It would be significantly advantageous to provide an alternative and combination gutta percha point and method for selection and application that has a broader spectrum of effectiveness based upon the clinical symptomatology, to thereby combat the bacterial contamination of leakage and reinfection.
According to the present invention, the above-described and other objects are accomplished by providing an improved gutta percha point comprising tetracycline and/or iodoform and method for application of the same that yields a broader spectrum of effectiveness based upon the clinical symptomatology in combating the bacterial contamination of leakage and reinfection. A method of preparation of a compule and delivery by a cannula is also disclosed that allows the dentist to select the properly medicated gutta percha point for the individual case.